1. Field of the Invention
This invention relates to a slider tester for inspecting a slider of a disk drive used in an information processing apparatus or the like.
2. Description of the Related Art
A hard disk drive (HDD) includes a disk that functions as a recording medium, disk drive suspension (hereinafter simply referred to as the suspension), actuator arm on which the suspension is mounted, etc. Data is magnetically recorded on the disk. A slider is mounted on the distal end portion of the suspension. This slider is provided with a magnetoelectric element used to access data to a recording surface of the disk, that is, an element for writing or reading data.
The suspension includes a base plate fixed to the actuator arm, load beam attached to the base plate, flexure located along the load beam, etc. The slider is mounted on a tongue (gimbal portion) formed on the flexure. When the disk is rotated at high speed by a spindle motor, the slider is caused to fly slightly above the surface of the disk by air that flows between the disk and slider, thereby forming an air bearing between the disk and slider. The flying height of the slider is kept within an appropriate range.
Before the suspension is incorporated into an actual disk drive, the slider is checked for acceptability by means of a slider tester. An example of a conventional slider tester is disclosed in Jpn. Pat. Appln. KOKAI Publication No. 2004-86976 (Patent Document 1). In this slider tester, a slider is fixed to an arm portion so as to share the same conditions with an actual suspension. A magnetic disk is rotated so that the slider flies, and the properties of the slider are measured.
On the other hand, a slider tester (slider supporting device) disclosed in Jpn. Pat. Appln. KOKAI Publication No. 2005-322377 (Patent Document 2) includes dummy load beams, flexures, etc., constructed in the same manner as those of actual suspensions. This slider tester is configured so that a slider can be removably attached thereto. In the slider tester, a disk is rotated with the slider mounted on a suspension, and various inspections are conducted with the slider flying above the surface of the disk. Any slider judged to be unacceptable by these inspections is rejected.
Only one slider can be mounted in each of the slider testers described in Patent Documents 1 and 2. The properties of the slider are measured by accessing the recording surface of the disk with a magnetoelectric element of the slider after the slider is moved to a predetermined position above the disk. After the measurement, the slider is moved to its original position and removed from the tester. Conventionally, therefore, each slider is singly mounted in the tester as it is tested. Thus, testing a plurality of sliders is not efficient and requires a long time.
In order to improve the efficiency of the slider inspection operation, an attempt was made to provide a common table with a plurality of suspensions for a tester each mounted with a slider. A plurality of sliders simultaneously move to a region above the recording surface of the disk as the table is moved radially relative to the disk (or along the track width). However, the peripheral rotational speed of the disk varies considerably between the inner and outer peripheral sides. The flying height of the slider depends on the peripheral rotational speed of the disk. Thus, the flying height of the slider that is moved to, for example, the inner peripheral portion of the disk tends to become smaller than when the slider is at the outer peripheral portion.
It conducting a read/write test for the slider using the radial central part of the disk, the flying height is adjusted to an appropriate value based on the radial intermediate part. If the slider moves to the inner peripheral side of the disk, therefore, its flying height becomes smaller than the appropriate value. In consequence, the slider may interfere with the recording surface of the disk.